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Volume 10
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J. Mar. Sci. Eng., Volume 10, Issue 2 (February 2022) – 181 articles

Cover Story (view full-size image): Polyplacophorans, commonly known as chitons, are benthic marine molluscs characterized by their eight articulated dorsal shell plates surrounded by a flexible marginal girdle. To obtain new information about the scantily studied digestive system of chitons, the oesophagus, stomach and intestine of Chaetopleura angulata and Acanthochitona fascicularis were investigated. Light and transmission electron microscopy techniques were used to morphologically and histochemically characterise the diverse cell types found in the digestive tract epithelium, which consist of absorptive cells, secretory cells and basal cells with enteroendocrine features. Additionally, stomach content examination in both species revealed a previously unknown omnivorous diet. View this paper.
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16 pages, 21388 KiB  
Article
Investigation on a Large-Scale Braceless-TLP Floating Offshore Wind Turbine at Intermediate Water Depth
by Yiming Zhou, Yajun Ren, Wei Shi and Xin Li
J. Mar. Sci. Eng. 2022, 10(2), 302; https://doi.org/10.3390/jmse10020302 - 21 Feb 2022
Cited by 3 | Viewed by 4672
Abstract
Tension leg platform (TLP) is a cost-effective and high-performance support structure for floating offshore wind turbine (FOWT) because of its small responses in heave, pitch, and roll with the constraint of the tendons. China, as the largest market of offshore wind energy, has [...] Read more.
Tension leg platform (TLP) is a cost-effective and high-performance support structure for floating offshore wind turbine (FOWT) because of its small responses in heave, pitch, and roll with the constraint of the tendons. China, as the largest market of offshore wind energy, has shown a demand for developing reliable, viable floating platform support structures, especially aiming at the intermediate water depth. The present paper described a newly proposed 10-MW Braceless-TLP FOWT designed for a moderate water depth of 60 m. The numerical simulations of the FOWT are carried out using the coupled aero-hydro-servo-elastic-mooring calculation tool FAST. The measured wind and wave data of the target site close to the Fujian Province of China were used to evaluate the performance of the FOWT under the 100-, 50-, 5-, and 2-year-return stochastic weather conditions. The natural periods of the platform in surge, sway, heave, pitch, roll, and yaw were found to be within the range recommended by the design standard DNV-RP-0286 Coupled Analysis of Floating Wind Turbines. The largest surge of the water depth ratio among all the load cases was 15%, which was smaller than the admissible ratio of 23%. The tower top displacements remained between −1 m and 1 m, which were at a similar order to those of a 10-MW monopile-supported offshore wind turbine. The six tendons remained tensioned during the simulation, even under the operational and extreme (parked) environmental conditions. The Braceless-TLP FOWT showed an overall satisfying performance in terms of the structural stability and illustrates the feasibility of this type of FOWT at such a moderate water depth. Full article
(This article belongs to the Special Issue Offshore Wind Turbine Foundations)
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15 pages, 2266 KiB  
Article
Growth Heterogeneity of Chub Mackerel (Scomber japonicus) in the Northwest Pacific Ocean
by Kai Cai, Richard Kindong, Qiuyun Ma, Xiaobin Han and Song Qin
J. Mar. Sci. Eng. 2022, 10(2), 301; https://doi.org/10.3390/jmse10020301 - 21 Feb 2022
Cited by 6 | Viewed by 2859
Abstract
Chub mackerel (Scomber japonicus) is a pelagic fish widely distributed in temperate and subtropical zones throughout the Indian and Pacific Oceans and is commercially exploited, particularly in the North Pacific. Although highly targeted in this region, little is known about their [...] Read more.
Chub mackerel (Scomber japonicus) is a pelagic fish widely distributed in temperate and subtropical zones throughout the Indian and Pacific Oceans and is commercially exploited, particularly in the North Pacific. Although highly targeted in this region, little is known about their life history aspects. The objectives of this study are to evaluate the growth heterogeneities and ageing analysis of this species. We describe the length-at-age, weight-at-length, relative condition factor relationships, spatiotemporal heterogeneity and compare estimated growth parameter values to those reported from other regions. This study used data obtained from Chinese fishing vessels collected from 2016–2020 in the northwest Pacific Ocean. Length-weight data from 2686 specimens (40–294 mm, fork length; 0.8–311.8 g body weight) were analyzed, and the Length-weight relationship was W = (1.41 × 10−6) × FL3.37. Seven linear mixed-effects models (LMEM) were used to analyze the heterogeneity of length-weight relationships of Chub mackerel. The Length-weight relationships for Chub mackerel were best described by a model with random effects with both year and season (spring, summer, autumn) with the scalar parameter a. Age estimates were obtained from 175 specimens, and the length-at-estimated ages relationship was described using three non-linear candidate growth models. The von Bertalanffy growth model fit the data best for Chub mackerel in the northwest Pacific Ocean. Comparing the results to that of previous studies, we observed that individual Chub mackerel exhibited a slower growth rate than that observed in previous studies. In addition, relative condition factors varied among years, seasons, and regions. Information presented in this study provides an effective scientific basis for stock assessment and fishery management of Chub mackerel in the northwest Pacific Ocean. Full article
(This article belongs to the Special Issue Marine Fish and Invertebrate Aquaculture)
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22 pages, 10789 KiB  
Article
A Fish and Dolphin Biophony in the Boat Noise-Dominated Soundscape of the Cres-Lošinj Archipelago (Croatia)
by Marta Picciulin, Marta Bolgan, Nikolina Rako-Gospić, Antonio Petrizzo, Marko Radulović and Raffaela Falkner
J. Mar. Sci. Eng. 2022, 10(2), 300; https://doi.org/10.3390/jmse10020300 - 21 Feb 2022
Cited by 8 | Viewed by 3534
Abstract
Spatio-temporal variability of marine soundscapes reflects environmental dynamics and local habitat health. This study characterizes the coastal soundscape of the Cres-Lošinj Natura 2000 Site of Community Importance, encompassing the non-tourist (11–15 March 2020) and the tourist (26–30 July 2020) season. A total of [...] Read more.
Spatio-temporal variability of marine soundscapes reflects environmental dynamics and local habitat health. This study characterizes the coastal soundscape of the Cres-Lošinj Natura 2000 Site of Community Importance, encompassing the non-tourist (11–15 March 2020) and the tourist (26–30 July 2020) season. A total of 240 h of continuous recordings was manually analyzed and the abundance of animal vocalizations and boat noise was obtained; sound pressure levels were calculated for the low (63–2000 Hz) and high (2000–20,000 Hz) frequency range. Two fish sound types were drivers of both seasonal and diel variability of the low-frequency soundscape. The first is emitted by the cryptic Roche’s snake blenny (Ophidion rochei), while the second, whose emitter remains unknown, was previously only described in canyons and coralligenous habitats of the Western Mediterranean Sea. The high-frequency bands were characterized by bottlenose dolphin (Tursiops truncatus) vocalizations, indicating dolphins’ use of area for various purposes. Boat noise, however, dominated the local soundscape along the whole considered periods and higher sound pressure levels were found during the Tourist season. Human-generated noise pollution, which has been previously found 10 years ago, is still present in the area and this urges management actions. Full article
(This article belongs to the Special Issue Passive Acoustics to Study Marine and Freshwater Ecosystems)
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21 pages, 4186 KiB  
Article
Predicting the Instability Trajectory of an Obliquely Loaded Pipeline on a Clayey Seabed
by Ning Wang, Wengang Qi and Fuping Gao
J. Mar. Sci. Eng. 2022, 10(2), 299; https://doi.org/10.3390/jmse10020299 - 21 Feb 2022
Cited by 4 | Viewed by 1932
Abstract
Predicting the instability trajectory of an obliquely loaded pipeline on the seabed is vital for the global buckling assessment. To numerically investigate the obliquely loaded pipe–soil interactions, a plane strain elastoplastic finite element model incorporating the adaptive meshing technique and the contact-pair algorithm [...] Read more.
Predicting the instability trajectory of an obliquely loaded pipeline on the seabed is vital for the global buckling assessment. To numerically investigate the obliquely loaded pipe–soil interactions, a plane strain elastoplastic finite element model incorporating the adaptive meshing technique and the contact-pair algorithm is employed and verified with the existing experimental data and the analytical predictions. The evolution of slip mechanisms within the underlying soil is simulated, indicating the instability direction of the pipe, and the corresponding ultimate soil resistance is closely correlated. It is also indicated that the ultimate load angle is in the positive correlation with the movement angle, the dimensionless embedment of the pipe and the roughness coefficient of the pipe–soil interface. On the basis of numerous simulations, a force-resultant plasticity model including the bearing capacity envelope and the flow rule is proposed for predicting the behavior of a partially embedded pipeline on the clayey seabed. Finally, an explicit expression with respect to the critical submerged weight of the pipe is derived for distinguishing the lateral instability of a pipe between the ‘light’ and the ‘heavy’ mode. Full article
(This article belongs to the Special Issue Feature Papers in Ocean Engineering)
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23 pages, 4981 KiB  
Article
Establishing a Risk Assessment Framework for Marine Assets and Assessing Typhoon Lekima Storm Surge for the Laizhou Bay Coastal Area of the Bohai Sea, China
by Jian Li, Dongxue Mo, Rui Li, Yijun Hou and Qingrong Liu
J. Mar. Sci. Eng. 2022, 10(2), 298; https://doi.org/10.3390/jmse10020298 - 21 Feb 2022
Cited by 1 | Viewed by 2127
Abstract
Effective risk assessment can reduce the economic losses and physical damage caused by marine dynamic processes, such as storm surges. Most risk assessments of marine disasters are based on regional parameters and discrete hazard grades. Targeted, multilevel, and multiangle risk assessments are urgently [...] Read more.
Effective risk assessment can reduce the economic losses and physical damage caused by marine dynamic processes, such as storm surges. Most risk assessments of marine disasters are based on regional parameters and discrete hazard grades. Targeted, multilevel, and multiangle risk assessments are urgently needed. This study focuses on specific types of affected infrastructure. We established a sensitivity matrix by considering the effects of different disaster causal factors on different types of affected infrastructure. Through this matrix, hazards, vulnerability, and emergency response and recovery capability were effectively combined in a risk assessment framework. We completed the risk calculation for multiple concurrent effects of disasters in areas with superimposed key infrastructure using complementary risk superposition. The hazard grade, vulnerability grade, and coefficient of emergency response and recovery capability were established based on the means of return period, characteristics of disaster distribution, types of affected infrastructure and disaster relief distance, and were continuous by solving functions, normal cumulative distributions, and analytic functions. On the basis of reasonable MIKE21 numerical simulation and abstract spatial distribution of vulnerable assets, we tested the rationality of the assessment system in the Lekima typhoon storm surge process. The results showed that the assessment system accurately reflected the risk of damage to the important infrastructure in terms of spatial distribution. Therefore, this risk assessment framework was suitable for the assessment of a marine dynamic disaster process in the lower Laizhou Bay coastal area of the Bohai Sea, China. Moreover, it provided a reference for disaster prevention and reduction, guided the way for decision making, and effectively reduced disaster losses. Full article
(This article belongs to the Special Issue Data Modelling for Coastal-Ocean Environments and Disasters)
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26 pages, 2351 KiB  
Review
Management and Sustainable Exploitation of Marine Environments through Smart Monitoring and Automation
by Francesca Glaviano, Roberta Esposito, Anna Di Cosmo, Francesco Esposito, Luca Gerevini, Andrea Ria, Mario Molinara, Paolo Bruschi, Maria Costantini and Valerio Zupo
J. Mar. Sci. Eng. 2022, 10(2), 297; https://doi.org/10.3390/jmse10020297 - 21 Feb 2022
Cited by 32 | Viewed by 6416
Abstract
Monitoring of aquatic ecosystems has been historically accomplished by intensive campaigns of direct measurements (by probes and other boat instruments) and indirect extensive methods such as aero-photogrammetry and satellite detection. These measurements characterized the research in the last century, with significant but limited [...] Read more.
Monitoring of aquatic ecosystems has been historically accomplished by intensive campaigns of direct measurements (by probes and other boat instruments) and indirect extensive methods such as aero-photogrammetry and satellite detection. These measurements characterized the research in the last century, with significant but limited improvements within those technological boundaries. The newest advances in the field of smart devices and increased networking capabilities provided by emerging tools, such as the Internet of Things (IoT), offer increasing opportunities to provide accurate and precise measurements over larger areas. These perspectives also correspond to an increasing need to promptly respond to frequent catastrophic impacts produced by drilling stations and intense transportation activities of dangerous materials over ocean routes. The shape of coastal ecosystems continuously varies due to increasing anthropic activities and climatic changes, aside from touristic activities, industrial impacts, and conservation practices. Smart buoy networks (SBNs), autonomous underwater vehicles (AUVs), and multi-sensor microsystems (MSMs) such as smart cable water (SCW) are able to learn specific patterns of ecological conditions, along with electronic “noses”, permitting them to set innovative low-cost monitoring stations reacting in real time to the signals of marine environments by autonomously adapting their monitoring programs and eventually sending alarm messages to prompt human intervention. These opportunities, according to multimodal scenarios, are dramatically changing both the coastal monitoring operations and the investigations over large oceanic areas by yielding huge amounts of information and partially computing them in order to provide intelligent responses. However, the major effects of these tools on the management of marine environments are still to be realized, and they are likely to become evident in the next decade. In this review, we examined from an ecological perspective the most striking innovations applied by various research groups around the world and analyzed their advantages and limits to depict scenarios of monitoring activities made possible for the next decade. Full article
(This article belongs to the Special Issue Marine Environment Monitoring)
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16 pages, 11215 KiB  
Article
Numerical Simulation Study of a Swirling Drill Bit Used for Ice Core Drilling
by Mengke Wang, Wenbo He, Minqi Wang, Jine Cao and Pinlu Cao
J. Mar. Sci. Eng. 2022, 10(2), 296; https://doi.org/10.3390/jmse10020296 - 21 Feb 2022
Cited by 1 | Viewed by 1952
Abstract
Due to its high mechanical penetration rate and lack of pollution of the environment, air reverse circulation drilling is considered to be a promising method for ice drilling. The air reverse circulation is caused by the combination of the ejector and the flushing [...] Read more.
Due to its high mechanical penetration rate and lack of pollution of the environment, air reverse circulation drilling is considered to be a promising method for ice drilling. The air reverse circulation is caused by the combination of the ejector and the flushing nozzles in the drill bit. In this paper, CFD software was used to simulate the influence of the structure of the swirler on the effect of air reverse circulation in the swirling drill bit, and a testing stand was established for the testing of air reverse circulation. The results show that for drill bits without flushing nozzles, the smaller the helical angle is, the larger the entrainment ratio will be, meanwhile the smaller the area ratio is, the larger the entrainment ratio will be. In contrast, for drill bits designed with flushing nozzles, the larger the helical angle is, the larger the entrainment ratio will be, and the larger the area ratio is, the larger the entrainment ratio will be. In addition, the presence of the ice core sharply reduces the effect of air reverse circulation. When the ice core’s height exceeds that of the outlet of the swirler, the reverse circulation effect is slightly improved. Full article
(This article belongs to the Section Ocean Engineering)
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18 pages, 4117 KiB  
Article
Ship Traffic Flow Prediction in Wind Farms Water Area Based on Spatiotemporal Dependence
by Tian Xu and Qingnian Zhang
J. Mar. Sci. Eng. 2022, 10(2), 295; https://doi.org/10.3390/jmse10020295 - 21 Feb 2022
Cited by 13 | Viewed by 2599
Abstract
To analyze the changing characteristics of ship traffic flow in wind farms water area, and to improve the accuracy of ship traffic flow prediction, a Gated Recurrent Unit (GRU) of a Recurrent Neural Network (RNN) was established to analyze multiple traffic flow sections [...] Read more.
To analyze the changing characteristics of ship traffic flow in wind farms water area, and to improve the accuracy of ship traffic flow prediction, a Gated Recurrent Unit (GRU) of a Recurrent Neural Network (RNN) was established to analyze multiple traffic flow sections in complex waters based on their traffic flow structure. Herein, we construct a spatiotemporal dependence feature matrix to predict ship traffic flow instead of the traditional ship traffic flow time series as the input of the neural network. The model was used to predict the ship traffic flow in the water area of wind farms in Yancheng city, Jiangsu Province. Autoregressive Integrated Moving Average (ARIMA), Support-Vector Machine (SVM) and Long Short-Term Memory (LSTM) were chosen as the control tests. The GRU method based on the spatiotemporal dependence is more accurate than the current mainstream ship traffic flow prediction methods. The results verify the reliability and validity of the GRU method. Full article
(This article belongs to the Special Issue Data/Knowledge-Driven Behaviour Analysis for Maritime Autonomous Surface Ships)
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14 pages, 16547 KiB  
Article
Ship Steering Adaptive CGS Control Based on EKF Identification Method
by Wei Guan, Haowen Peng, Xianku Zhang and Hui Sun
J. Mar. Sci. Eng. 2022, 10(2), 294; https://doi.org/10.3390/jmse10020294 - 20 Feb 2022
Cited by 17 | Viewed by 2703
Abstract
In recent years, marine autonomous surface vessels (MASS) have grown into a ship research issue to increase the level of autonomy of ship behavior decision-making and control while sailing at sea. This paper focuses on the MASS motion control module design that aims [...] Read more.
In recent years, marine autonomous surface vessels (MASS) have grown into a ship research issue to increase the level of autonomy of ship behavior decision-making and control while sailing at sea. This paper focuses on the MASS motion control module design that aims to improve the accuracy and reliability of ship steering control systems. Nevertheless, the stochastic sea and wind environment have led to the extensive use of filters and state observers for estimating the ship-motion-related parameters, which are important for ship steering control systems. In particular, the ship maneuverability Nomoto index, which primarily determines the designed ship steering controller’s performance, cannot be observed directly due to the model errors and the external environment disturbance in the process of sailing. Hence, an adaptive robust ship steering controller based on a closed-loop gain shaping (CGS) scheme and an extended Kalman filter (EKF) on-line identification method is explored in this paper. To verify the effectiveness of the proposed steering controller design scheme, the motor vessel YUKUN was taken as the control plant and a series of simulation experiments were carried out. The results show the advantages of the dynamic response performance of the proposed steering controller compared with the classical PD and traditional CGS controllers. Therefore, the proposed adaptive CGS steering controller would be a good solution for MASS motion control module design. Full article
(This article belongs to the Special Issue Control Theory and Applications in Marine Autonomous Vehicles)
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20 pages, 3492 KiB  
Article
Optimization of the Wake Oscillator for Transversal VIV
by Victoria Kurushina, Andrey Postnikov, Guilherme Rosa Franzini and Ekaterina Pavlovskaia
J. Mar. Sci. Eng. 2022, 10(2), 293; https://doi.org/10.3390/jmse10020293 - 20 Feb 2022
Cited by 11 | Viewed by 2318
Abstract
Vibrations of slender structures associated with the external flow present a design challenge for the energy production systems placed in the marine environment. The current study explores the accuracy of the semi-empirical wake oscillator models for vortex-induced vibrations (VIV) based on the optimization [...] Read more.
Vibrations of slender structures associated with the external flow present a design challenge for the energy production systems placed in the marine environment. The current study explores the accuracy of the semi-empirical wake oscillator models for vortex-induced vibrations (VIV) based on the optimization of (a) the damping term and (b) empirical coefficients in the fluid equation. This work investigates the effect of ten fluid damping variations, from the classic van der Pol to more sophisticated fifth-order terms, and prediction of the simplified case of the VIV of transversally oscillating rigid structures provides an opportunity for an extended, comprehensive comparison of the performance of tuned models. A constrained nonlinear minimization algorithm in MATLAB is applied to calibrate considered models using the published experimental data, and the weighted objective function is formulated for three different mass ratios. Comparison with several sources of published experimental data for cross-flow oscillations confirms the model accuracy in the mass ratio range. The study indicates the advantageous performance of the models tuned with the medium mass ratio data and highlights some advantages of the Krenk–Nielsen wake oscillator. Full article
(This article belongs to the Section Ocean Engineering)
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21 pages, 4254 KiB  
Article
Numerical and Experimental Study of Hydrodynamic Response for a Novel Buoyancy-Distributed Floating Foundation Based on the Potential Theory
by Xiaobin Qu and Yingxue Yao
J. Mar. Sci. Eng. 2022, 10(2), 292; https://doi.org/10.3390/jmse10020292 - 19 Feb 2022
Cited by 3 | Viewed by 2891
Abstract
Floating foundations play a vital role in exploring offshore energy. After analyzing various floating foundation concepts, this paper presents a novel buoyancy-distributed floating foundation (BDFF) inspired by the decentralized concept. The calculations of a floating system based on the BDFF design were performed [...] Read more.
Floating foundations play a vital role in exploring offshore energy. After analyzing various floating foundation concepts, this paper presents a novel buoyancy-distributed floating foundation (BDFF) inspired by the decentralized concept. The calculations of a floating system based on the BDFF design were performed for a series of wave conditions. The potential theory and the boundary element method (BEM) were used in the numerical progress. A broader view was focused on the impacts of wave frequency and wave directions on the system. The proposed floating system was further validated through wave tests in a wave tank, showing that the potential theory can satisfactorily predict the RAOs in regular waves. Moreover, numerical results and experimental results were compared with a conventional SPAR. Finally, the coupling relationship between six degrees of freedom was described. Full article
(This article belongs to the Section Ocean Engineering)
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17 pages, 4598 KiB  
Article
Zooplankton Population and Community Structure Changes in Response to a Harmful Algal Bloom Caused by Prorocentrum donghaiense in the East China Sea
by Anglu Shen, Wenwen Chen, Yongjiu Xu and Kin-Chung Ho
J. Mar. Sci. Eng. 2022, 10(2), 291; https://doi.org/10.3390/jmse10020291 - 19 Feb 2022
Cited by 7 | Viewed by 2457
Abstract
Blooms of the dinoflagellate Prorocentrum donghaiense have had adverse impacts on marine ecosystems. However, ecological details, particularly the impacts and processes of the P. donghaiense bloom on the zooplankton community structure are poorly known. We investigated the changes of zooplankton communities in situ [...] Read more.
Blooms of the dinoflagellate Prorocentrum donghaiense have had adverse impacts on marine ecosystems. However, ecological details, particularly the impacts and processes of the P. donghaiense bloom on the zooplankton community structure are poorly known. We investigated the changes of zooplankton communities in situ within the whole process of a P. donghaiense bloom in the coastal waters in southern Zhejiang Province, China, in May 2016. Results showed that ecological changes during the blooms of P. donghaiense could be divided into three major phases, namely the growth, maintenance, and dissipation phases with regard to the cell abundance of P. donghaiense by bottle sampling of plankton. A total of 42 species of zooplankton were identified. The average abundance and species number of zooplankton in the growth phase were significantly higher than those in the maintenance and dissipation phases. It is shown that the top-two highest proportions of zooplankton in the growth phase were small jellyfishes and copepods, while small jellyfishes and chaetognaths, and copepoda larvae and chaetognaths were the top-two highest in the maintenance and dissipation phases respectively. However, the values of biodiversity index have no statistically significant differences between the three phases. The present results suggested that P. donghaiense bloom produced significant negative impacts on the abundance and species composition of zooplankton with particular reference to copepods. Full article
(This article belongs to the Special Issue Marine Harmful Algae)
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13 pages, 3348 KiB  
Article
Zonal Distribution Characteristics of Microplastics in the Southern Indian Ocean and the Influence of Ocean Current
by Jingxi Li, Fenglei Gao, Di Zhang, Wei Cao and Chang Zhao
J. Mar. Sci. Eng. 2022, 10(2), 290; https://doi.org/10.3390/jmse10020290 - 19 Feb 2022
Cited by 23 | Viewed by 4030
Abstract
As a new type of pollutant, microplastics widely exist in the marine environment and have attracted a lot of attention from the international community. In order to study the distribution of microplastics and the influence of ocean current, microplastic samples in seawater of [...] Read more.
As a new type of pollutant, microplastics widely exist in the marine environment and have attracted a lot of attention from the international community. In order to study the distribution of microplastics and the influence of ocean current, microplastic samples in seawater of the southern Indian Ocean were collected using a peristaltic pump equipped on-board and concentrated on site. Qualitative and quantitative analyses of microplastics were performed using a stereo-microscope and a micro-Fourier transform infrared spectroscope attenuated total reflection. The results showed that the average abundance of microplastics in seawater of the southern Indian Ocean was 2.3 ± 2.1 items/m3, which was consistent with that in other oceans. Polyethylene terephthalate (PET), polyethylene (PE), Rayon, polyamide (PA), and polyvinylidene chloride (PVDC) were the main polymers of microplastics in the southern Indian Ocean. The size range of all detected microplastics was 108.2–4703.0 µm. All microplastics had different colors, such as black, red, yellow, gray, blue, green, purple, and transparent. Fiber was the dominant shape of microplastics. The abundance distribution of microplastics fluctuated in the latitudinal direction. The abundance of microplastics from the present study area was higher in the coastal region of the South Africa continent and the Indian Ocean garbage patch, with an average abundance of 4.0 items/m3. The average abundance of microplastics was relatively high in the convergence area of the circulation, which revealed that the ocean current facilitated the agglomeration and transportation of microplastics. Full article
(This article belongs to the Special Issue Marine Microplastic)
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19 pages, 7055 KiB  
Article
Asymmetrical Oscillating Morphology Hydrodynamic Performance of a Novel Bionic Pectoral Fin
by Cheng Xing, Yong Cao, Yonghui Cao, Guang Pan and Qiaogao Huang
J. Mar. Sci. Eng. 2022, 10(2), 289; https://doi.org/10.3390/jmse10020289 - 19 Feb 2022
Cited by 24 | Viewed by 3124
Abstract
This research proposes a novel bionic pectoral fin and experimentally studied the effects of the oscillation parameters on the hydrodynamic performance of a bionic experimental prototype. Inspired by manta rays, the bionic pectoral fin was simplified and modeled based on the natural pectoral [...] Read more.
This research proposes a novel bionic pectoral fin and experimentally studied the effects of the oscillation parameters on the hydrodynamic performance of a bionic experimental prototype. Inspired by manta rays, the bionic pectoral fin was simplified and modeled based on the natural pectoral fin skeleton structure and oscillation morphology of this underwater creature. A dual-degree-of-freedom bionic pectoral fin was designed. The active spatial motion was realized by the space six-link mechanism driven by two motors, and the passive deformation was achieved by carbon fiber. The motion analysis of the bionic pectoral fin proves that the pectoral fin can realize an “8”-shaped spatial trajectory. An experimental prototype was developed accordingly. The experimental prototype could flap between 0.1 Hz and 0.6 Hz and produce a maximum thrust of 20 N. The hydrodynamic performance under different oscillation parameters was studied experimentally in a water pool. The experimental results indicate that the hydrodynamic performance of the pectoral fin oscillation is closely related to the motion equation parameters including the amplitude, frequency, phase difference, and initial bias. In addition to considering the impact of parameters on thrust and lift, the influences of asymmetrical oscillation on the position of the equivalent point were also studied. The results show that the pectoral fin proposed in this research exhibited the expected spatial deformation and outstanding hydrodynamic performance. The obtained results shed light on the updated design and control of a bionic robot fish. Full article
(This article belongs to the Special Issue Frontiers in Deep-Sea Equipment and Technology)
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11 pages, 1269 KiB  
Review
Towards Risk Assessments of Microplastics in Bivalve Mollusks Globally
by Jinfeng Ding, Yunmei Sun, Changfei He, Jingxi Li and Fengmin Li
J. Mar. Sci. Eng. 2022, 10(2), 288; https://doi.org/10.3390/jmse10020288 - 19 Feb 2022
Cited by 51 | Viewed by 9114
Abstract
The ubiquitous presence of microplastics in bivalve mollusks and related risks have raised particular concerns. In this study, the available data on the abundance and polymer type of microplastics in bivalves from twenty-two countries were extracted to comprehensively understand the risks of microplastics [...] Read more.
The ubiquitous presence of microplastics in bivalve mollusks and related risks have raised particular concerns. In this study, the available data on the abundance and polymer type of microplastics in bivalves from twenty-two countries were extracted to comprehensively understand the risks of microplastics in bivalves. Following the data from 52 peer-reviewed papers, the abundance, chemical composition, and human exposure risks of microplastics of bivalves among countries were initially assessed. Abundance risk results indicated that bivalves from 22 countries presented a low pollution load index, showing a lower risk level (level I). The polymer risk index (H) of bivalves from Portugal (Hcountry = 1335, level IV) and India (Hcountry = 1187, level IV) were higher than the other countries due to the occurrence of hazardous microplastics, such as polyvinyl chloride. For the human exposure risks, the global mean value of microplastic exposure to humans via mollusk consumption is estimated to be 751 microplastics/capita/year, with the maximum intake by the Chinese. This study suggests that abundance risk may be a fundamental indicator for assessing the potential hazard to humans until the chemical composition risks are confirmed. This study is the first attempt to assess the potential risks of microplastics in bivalves using three evaluation models based on microplastic abundances and polymer types, which will contribute to establishing future human health risk assessment frameworks. These findings will also assist efforts in policy-making to minimize microplastic risks in seafood. Full article
(This article belongs to the Special Issue Marine Microplastic)
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22 pages, 11797 KiB  
Article
Short-Term Variations in Water Temperature of the Antarctic Surface Layer
by Yuyi Hu, Weizeng Shao, Jun Li, Chunling Zhang, Lingqiao Cheng and Qiyan Ji
J. Mar. Sci. Eng. 2022, 10(2), 287; https://doi.org/10.3390/jmse10020287 - 18 Feb 2022
Cited by 8 | Viewed by 2252
Abstract
Against the background of global climate change, the warming water temperature of Antarctic surface water (<500 m) is worthy of study. Therefore, the purpose of this study was to investigate short-term variations in the water temperature of Antarctic surface water from January 2000 [...] Read more.
Against the background of global climate change, the warming water temperature of Antarctic surface water (<500 m) is worthy of study. Therefore, the purpose of this study was to investigate short-term variations in the water temperature of Antarctic surface water from January 2000 to December 2016, using offline coupled ocean models, i.e., the WAVEWATCH-III (WW3) model and the Stony Brook Parallel Ocean Model (sbPOM). The validation of the WW3-simulated significant wave height (SWH) against the measurements from the Jason-2 altimeter produced a root mean square error (RMSE) of 0.39 m with a 0.30-m bias. Moreover, the sbPOM-simulated water temperatures were compared with the collocated measurements from Argo buoys, yielding, and RMSE for water temperatures of less than 1.0 °C and a correlation coefficient (COR) of 0.92. The annual variation in the sbPOM-simulated water temperatures of the Antarctic surface water layer showed that the sea surface temperatures (SSTs) of the Pacific Ocean and Atlantic Ocean were greater than the SST of the Indian Ocean. Moreover, the SST rapidly increased to 2 °C in the Pacific Ocean in specific years due to El Nino and La Nina events. The vertical profile of the water temperature showed that the depth of the cool water in the Indian Ocean has decreased to 100 m since 2008, while the depth in the Pacific Ocean and Atlantic Ocean is about 200 m. It was also found that the seasonal variations in the water temperature at depths of 0 m, 50 m, and 100 m in the Pacific Ocean were more sensitive to El Nino events between January and June. However, it was revealed in this work that the increasing intensity of El Nino and La Nina events could reduce water warming in the Pacific Ocean. Full article
(This article belongs to the Special Issue Monitoring and Assessing the Changing Coastal Ecosystem in Response to Global Change)
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16 pages, 3088 KiB  
Article
Mapping of Greek Marine Finfish Farms and Their Potential Impact on the Marine Environment
by George Katselis, Konstantinos Tsolakos and John A. Theodorou
J. Mar. Sci. Eng. 2022, 10(2), 286; https://doi.org/10.3390/jmse10020286 - 18 Feb 2022
Cited by 6 | Viewed by 3770
Abstract
The Greek marine aquaculture has a leading role in the Mediterranean mariculture industry, mainly in the export sector and its prominent contribution to the country’s economy. In the present study, the spatial distribution of Greek finfish farming activity and its potential impact zones [...] Read more.
The Greek marine aquaculture has a leading role in the Mediterranean mariculture industry, mainly in the export sector and its prominent contribution to the country’s economy. In the present study, the spatial distribution of Greek finfish farming activity and its potential impact zones on the marine environment were estimated and mapped. The Greek coastline was scanned via Google Earth satellite images for the period of June 2016 to May 2017, with 433 fish farm cage arrays being detected. For each cage array, the zones at different distances corresponding to various type of impacts were mapped by means of GIS technologies. Seventy-five spatial clusters of cage arrays (sc) were revealed, including cage arrays with shown connectivity. As per the findings, Greek marine fish farming activity shows a high level of spatial aggregation but with a relative moderate intensity of impacts due to legal constraints, which play a crucial role in controlling the spatial distribution of activity at a local, regional, and national scale. The results reflect an important source of geodata, necessary for the spatial planning of activity, the monitoring of environmental impacts, and the research itself. Full article
(This article belongs to the Special Issue Marine Fish and Invertebrate Aquaculture)
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16 pages, 3192 KiB  
Article
Course Control of a Manta Robot Based on Amplitude and Phase Differences
by Yiwei Hao, Yong Cao, Yonghui Cao, Qiaogao Huang and Guang Pan
J. Mar. Sci. Eng. 2022, 10(2), 285; https://doi.org/10.3390/jmse10020285 - 18 Feb 2022
Cited by 22 | Viewed by 3188
Abstract
Due to external interference, such as waves, the success of underwater missions depends on the turning performance of the vehicle. Manta rays use two broad pectoral fins for propulsion, which provide better anti-interference ability and turning performance. Inspired by biological yaw modes, we [...] Read more.
Due to external interference, such as waves, the success of underwater missions depends on the turning performance of the vehicle. Manta rays use two broad pectoral fins for propulsion, which provide better anti-interference ability and turning performance. Inspired by biological yaw modes, we use the phase difference between the pectoral fins to realize fast course adjustment and the amplitude difference to realize precise adjustment. We design a bionic robot with pectoral fins and use phase oscillators to realize rhythmic motion. An expected phase difference transition equation is introduced to realize a fast and smooth transition of the output, and the parameters are adjusted online. We combine the phase difference and amplitude difference yaw modes to realize closed-loop course control. Through course interference and adjustment experiments, it is verified that the combined mode is more effective than a single mode. Finally, a rectangular trajectory swimming experiment demonstrates continuous mobility of the robot under the combined mode. Full article
(This article belongs to the Section Ocean Engineering)
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16 pages, 5634 KiB  
Article
Response of 5 MW Floating Wind Turbines to Combined Action of Wind and Rain
by Song Wu, Hanbing Sun and Xinyu Li
J. Mar. Sci. Eng. 2022, 10(2), 284; https://doi.org/10.3390/jmse10020284 - 18 Feb 2022
Cited by 3 | Viewed by 1781
Abstract
For 5 MW floating wind turbines, the load response is significantly affected by wind and rain conditions. In order to reveal the relevant regularity of windblown rain and analyze the load response after being affected by the wind and rain, the rain phase [...] Read more.
For 5 MW floating wind turbines, the load response is significantly affected by wind and rain conditions. In order to reveal the relevant regularity of windblown rain and analyze the load response after being affected by the wind and rain, the rain phase is regarded as a continuous phase to be simulated. The self-compiled solver WARFoam (Wind and Rain Foam) is used to simulate the 5 MW wind turbines under wind and rain conditions. It is based on the Euler multiphase-model theory and the algorithm of unidirectional coupling of wind and rain. In this paper, the results of aerodynamic loads under WAR conditions are compared with the results of using the Lagrange particle-tracking model in order to prove that the Euler multiphase model can accurately calculate rain loads. On the basis of comparative verification, the convergence of the self-compiled solver is verified, which proves that the load-response analysis of the wind turbines under wind and rain conditions is accurate and efficient. The results show that rain has a significant impact on the load response of the wind turbines. Finally, the simulation results obtain the envelope diagram of the influence coefficient of rain-induced loads, which provides a quantitative reference standard for the calculation of the loads under wind and rain conditions. Full article
(This article belongs to the Section Ocean Engineering)
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21 pages, 1517 KiB  
Article
An Automatic Search and Energy-Saving Continuous Tracking Algorithm for Underwater Targets Based on Prediction and Neural Network
by Haiming Liu, Bo Xu and Bin Liu
J. Mar. Sci. Eng. 2022, 10(2), 283; https://doi.org/10.3390/jmse10020283 - 18 Feb 2022
Cited by 9 | Viewed by 1910
Abstract
Underwater target search and tracking has become a technical hotspot in underwater sensor networks (UWSNs). Unfortunately, the complex and changeable marine environment creates many obstacles for localization and tracking. This paper proposes an automatic search and energy-saving continuous tracking algorithm for underwater targets [...] Read more.
Underwater target search and tracking has become a technical hotspot in underwater sensor networks (UWSNs). Unfortunately, the complex and changeable marine environment creates many obstacles for localization and tracking. This paper proposes an automatic search and energy-saving continuous tracking algorithm for underwater targets based on prediction and neural network (ST-BPN). Firstly, the network contains active sensor nodes that can transmit detection signal. When analyzing the reflected signal spectrum, a modified convolutional neural network M-CNN is built to search the target. Then, based on the relationship between propagation delay and target location, a localization algorithm which can resist the influence of clock asynchrony LA-AIC is designed. Thirdly, a scheme based on consensus filtering TS-PSMCF is used to track the target. It is worth mentioning that a predictive switching mechanism, PSM, is added to the tracking process to adjust the working state of nodes. Simulation results show that the recognition accuracy of M-CNN is as high as 99.7%, the location accuracy of LA-AIC is 92.3% higher than that of traditional methods, and the tracking error of TS-PSMCF is kept between 0 m and 5 m. Full article
(This article belongs to the Special Issue Underwater Sensor Networks (UWSNs))
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14 pages, 7792 KiB  
Article
On-Site Investigations of Coastal Erosion and Accretion for the Northeast of Taiwan
by Ting-Yu Liang, Chih-Hsin Chang, Shih-Chun Hsiao, Wei-Po Huang, Tzu-Yin Chang, Wen-Dar Guo, Che-Hsin Liu, Jui-Yi Ho and Wei-Bo Chen
J. Mar. Sci. Eng. 2022, 10(2), 282; https://doi.org/10.3390/jmse10020282 - 18 Feb 2022
Cited by 12 | Viewed by 2824
Abstract
Coastal erosion is a major natural hazard along the northeastern shoreline (i.e., Yilan County) of Taiwan. Analyses of the evolution of the 0 m isobath of the Yilan County coastline indicate that erosion and accretion are occurring north and south of Wushi Fishery [...] Read more.
Coastal erosion is a major natural hazard along the northeastern shoreline (i.e., Yilan County) of Taiwan. Analyses of the evolution of the 0 m isobath of the Yilan County coastline indicate that erosion and accretion are occurring north and south of Wushi Fishery Port, respectively, because of jetty and groin construction. Topographic and bathymetric surveys involving the measurement of 43 cross sections were conducted in 2006, 2012, 2013, and 2019. The cross-shore profile comparisons reveal that the erosion of onshore dunes is significant in the northern Jhuan River estuary. Due to the establishment of a nature reserve in the southern Lanyang River estuary, the sediments are carried northward by tidal currents, and accretion is inevitable in the northern Lanyang River estuary. The results of the bathymetric surveys also suggest that the shoreline of Yilan County tends to accrete in summer because of abundant sediment from the rivers; however, it is eroded in winter, owing to the large waves induced by the northeast monsoon. Additionally, the calculated net volume of erosion and accretion between each pair of cross sections shows that the length of coastline impacted by estuarine sediment transport is approximately 2 km long from north to south along the coastline of the Lanyang River estuary. Full article
(This article belongs to the Special Issue Storm Tide and Wave Simulations and Assessment II)
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13 pages, 3068 KiB  
Article
Phylogeography and Genetic Structure of the Swimming Crabs Portunus sanguinolentus (Herbst, 1783) in East Asia
by Yu-Ming Lu, Chun-Han Shih, Po-Cheng Chen, Wei-Chieh Kao, Ying-Chou Lee, Yu-San Han and Tzong-Der Tzeng
J. Mar. Sci. Eng. 2022, 10(2), 281; https://doi.org/10.3390/jmse10020281 - 18 Feb 2022
Cited by 2 | Viewed by 2324
Abstract
The three-spot swimming crab (Portunus sanguinolentus) is mainly distributed in South East Asia. An analysis of mitochondrial control region partial sequences allows us to determine the population genetic structure, phylogeography and historical demography of this species in East Asia. The seven [...] Read more.
The three-spot swimming crab (Portunus sanguinolentus) is mainly distributed in South East Asia. An analysis of mitochondrial control region partial sequences allows us to determine the population genetic structure, phylogeography and historical demography of this species in East Asia. The seven populations, which included 110 individuals, were collected from mainland China (Shanghai, SH, Xiamen, XM and Hong Kong, HK), Taiwan (Yilan, YL, Taichung, TC, Donggang, DG) and Singapore (Singapore, SGP). The nucleotide diversity (π) of all individuals was 0.01149, with values ranging from 0.00372 (SGP) to 0.01345 (YL). In total, 90 haplotypes have been identified, which can be divided into two major lineages: lineage A consists of specimens from SH, YL, XM, TC and DG, and lineage B corresponds to specimen from SGP. From the second to the most recent interglacial period, population expansion was observed in each lineage. However, a low level of genetic differentiation was also observed in the three-spotted swimming crab, P. sanguinolentus, according to FST values. Our results suggest that several past and present habitat configurations have shaped the genetic patterns of P. sanguinolentus until now. During Pleistocene glaciations, when sea levels were low, this species may have moved along the coast from Southeast Asia to China. It first colonized the Hong Kong area during this era. After sea levels rose and shorelines receded, it subsequently spread to the coast of mainland China. Full article
(This article belongs to the Special Issue Marine Fisheries Management)
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17 pages, 12104 KiB  
Article
Experimental Evaluation of Shear Properties of Lightweight PVC Core for Marine Application Using Digital Image Correlation System
by Davor Bolf, Albert Zamarin, Paulina Krolo and Marko Hadjina
J. Mar. Sci. Eng. 2022, 10(2), 280; https://doi.org/10.3390/jmse10020280 - 17 Feb 2022
Cited by 2 | Viewed by 2935
Abstract
Sandwich structures are well-known and frequently used solutions in marine applications, especially when structural stiffness is required. An important part of the sandwich structure is the core, which usually carries shear loads. Therefore, choosing a reliable test method and knowing the exact shear [...] Read more.
Sandwich structures are well-known and frequently used solutions in marine applications, especially when structural stiffness is required. An important part of the sandwich structure is the core, which usually carries shear loads. Therefore, choosing a reliable test method and knowing the exact shear properties of the particular core used in the structural design is beneficial for every engineer. Shear properties of the FlexyFoam M-55, a closed-cell, lightweight PVC foam with an apparent density of 60 kg/m3, have been investigated according to the ASTM C273 standard, using the tensile and compressive loading of metal supporting plates glued to the PVC foam sample. A digital image correlation (DIC) technique was used to monitor the crack propagation, and the appearance of secondary stresses at the foam-adhesive interface and strain field for the representative sample was presented. Displacement was measured using the testing machine sensors and compared to the measurements from the DIC technique. Specimen manufacturing details, surface preparation, and the gluing sequence were described, and measuring equipment and experiment settings were presented. Stress-strain curves have been presented and shear modulus and ultimate shear strength of the foam were compared for each test approach. The results were discussed and compared with the manufacturer’s data, as well as with foams of similar densities. The well-established approach in testing the core material was discussed, and recommendations were given to improve the testing procedure. Full article
(This article belongs to the Section Ocean Engineering)
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18 pages, 586 KiB  
Article
Adaptive Auto-Berthing Control of Underactuated Vessel Based on Barrier Lyapunov Function
by Yang Liu, Nam-kyun Im, Qiang Zhang and Guibing Zhu
J. Mar. Sci. Eng. 2022, 10(2), 279; https://doi.org/10.3390/jmse10020279 - 17 Feb 2022
Cited by 9 | Viewed by 2392
Abstract
This paper investigates the automatic berthing problem of underactuated surface vessels in the case of uncertain dynamics and yaw rate limitation, given the importance of yaw rate control and the unmeasurable hydrodynamic parameters of the vessel at low speeds. First, we use the [...] Read more.
This paper investigates the automatic berthing problem of underactuated surface vessels in the case of uncertain dynamics and yaw rate limitation, given the importance of yaw rate control and the unmeasurable hydrodynamic parameters of the vessel at low speeds. First, we use the differential homeomorphism coordinate transformation to solve the problem of underactuation. Second, a radial basis function network (RBF) is introduced to approximate unknown nonlinear functions. Third, we apply the barrier Lyapunov function (BLF) approach to limit the yaw rate within a safe range. Fourth, we use dynamic surface control (DSC) technology and minimum learning parameters (MLP) to tackle the differential explosion problems in backstepping and computational complexity. Finally, Lyapunov stability theory proves that signals produced by the designed control scheme are bounded and effective. The simulation results show that, compared with the control scheme without BLF, the proposed method can effectively limit the yaw rate within a specific range and effectively solves the influence of the model uncertainly. Full article
(This article belongs to the Special Issue Control Theory and Applications in Marine Autonomous Vehicles)
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14 pages, 4772 KiB  
Article
Buckling and Post-Buckling Behavior of Perfect/Perforated Composite Cylindrical Shells under Hydrostatic Pressure
by Ke-Chun Shen, Zhao-Qi Yang, Lei-Lei Jiang and Guang Pan
J. Mar. Sci. Eng. 2022, 10(2), 278; https://doi.org/10.3390/jmse10020278 - 17 Feb 2022
Cited by 6 | Viewed by 2943
Abstract
In this paper, the buckling and post-buckling behavior of perfect and perforated composite cylindrical shells subjected to external hydrostatic pressure was experimentally investigated. Three filament wound composite cylindrical shells were fabricated from T700-12K Carbon fiber/Epoxy, two of which were perforated and reinforced. A [...] Read more.
In this paper, the buckling and post-buckling behavior of perfect and perforated composite cylindrical shells subjected to external hydrostatic pressure was experimentally investigated. Three filament wound composite cylindrical shells were fabricated from T700-12K Carbon fiber/Epoxy, two of which were perforated and reinforced. A test platform was established that allows researchers to observe the deformation of composite cylindrical shells under hydrostatic pressure in real-time during test. According to experimental observation, strain response and buckling deformation wave were discussed. Comparative analysis was carried out based on the experimental observation and finite element prediction. Results show that the deformation of composite cylindrical shell under hydrostatic pressure included linear compression, buckling and post-buckling processes. The buckling behavior was a progressive evolution process which accounted for 20% of the load history, and strain reversal phenomenon generally occurred at the trough of the buckling wave. As for the postbuckling deformation, the load carrying capacity of the shell gradually decreased while the magnitude of strain continued increasing. Both the perfect and perforated composite cylindrical shells collapsed at the trough of the buckling wave. Comparing with the perfect shell, it was validated the reinforcement design could effectively ensure the load carrying capacity of the perforated composite cylindrical shell. Full article
(This article belongs to the Special Issue Frontiers in Deep-Sea Equipment and Technology)
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12 pages, 1809 KiB  
Article
Effects of Suspended Particles on Exopolysaccharide Secretion of Two Microalgae in Jinjiang Estuary (Fujian, China)
by Jie Liu, Xiaoyu Han, Hui Xing, Yiting Nan, Jiahui Lin, Junming He, Sijia Chen, Yanfang Wei and Peiyong Guo
J. Mar. Sci. Eng. 2022, 10(2), 277; https://doi.org/10.3390/jmse10020277 - 17 Feb 2022
Cited by 1 | Viewed by 1717
Abstract
The effects of suspended particles (SP) of different concentrations and sizes on the secretion of exopolysaccharide (EPS) by Chlorella pyrenoidosa (C. pyrenoidosa) and Microcystis flos-aquae (M. flos-aquae) in Jinjiang Estuary, Fujian Province, China were studied in co-cultures of microalgae [...] Read more.
The effects of suspended particles (SP) of different concentrations and sizes on the secretion of exopolysaccharide (EPS) by Chlorella pyrenoidosa (C. pyrenoidosa) and Microcystis flos-aquae (M. flos-aquae) in Jinjiang Estuary, Fujian Province, China were studied in co-cultures of microalgae and SP. The results show that the SP concentration has an “inhibit–promote–inhibit” effect on the secretion of EPS by C. pyrenoidosa, whereby there is an optimal concentration of SP corresponding to the largest amount of EPS secreted by C. pyrenoidosa. Low concentrations had no significant effect on the secretion of EPS from M. flos-aquae (p > 0.05), whereas higher concentrations had an inhibitory effect. The C. pyrenoidosa EPS content was found to be significantly decreased in response to SP of small particle sizes (0–75 and 75–120 μm) and significantly increased for SP of large particle sizes (120–150 and 150–500 μm). Small particle sizes (0–75 and 75–120 μm) were found to be beneficial to the secretion of EPS from M. flos-aquae, and the promotion of EPS secretion gradually decreased with the increase in SP particle size. However, when the particle size was too large (120–150 and 150–500 μm), SP had no significant effect on EPS secretion. This study is helpful for understanding the microalgae EPS secretion response to SP and provides a scientific basis for studying the mechanism of EPS secretion by algae and the effect of SP on eutrophication of the estuary. Full article
(This article belongs to the Section Marine Biology)
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9 pages, 1249 KiB  
Article
Detection of Haplosporidium pinnae from Pinna nobilis Faeces
by Raquel Lopez-Nuñez, Emilio Cortés Melendreras, Francisca Giménez Casalduero, Patricia Prado, Federico Lopez-Moya and Luis Vicente Lopez-Llorca
J. Mar. Sci. Eng. 2022, 10(2), 276; https://doi.org/10.3390/jmse10020276 - 17 Feb 2022
Cited by 3 | Viewed by 2545
Abstract
Pinna nobilis (Linnaeus, 1758) is the largest bivalve endemic to the Mediterranean. It is distributed in a wide range of coastal environments, including estuaries. Pinna nobilis has recently become a critically endangered species (with almost 100% mortality) along the entire Spanish Mediterranean coast. [...] Read more.
Pinna nobilis (Linnaeus, 1758) is the largest bivalve endemic to the Mediterranean. It is distributed in a wide range of coastal environments, including estuaries. Pinna nobilis has recently become a critically endangered species (with almost 100% mortality) along the entire Spanish Mediterranean coast. This may be due to coinfections caused by Haplosporidium pinnae and bacterial pathogens such as Mycobacterium spp. We extensively sampled P. nobilis from Mar Menor lagoon (SE Spain), a site where individuals still survive. Using conventional PCR, we found Haplosporidium spp. in 7.1% of mantle and faecal DNA samples in different individuals of P. nobilis. We identified and quantified Haplosporidium pinnae in P. nobilis using Sanger sequencing and qPCR. Faecal H. pinnae detection is non-invasive, unlike biopsies. Therefore, this non-lethal and non-invasive sampling method could contribute to the welfare of living populations, particularly in eutrophic environments, where they are prone to septicaemia. The use of faecal DNA analysis could be a major advance in epidemiology and recovery assessment studies of P. nobilis. Full article
(This article belongs to the Special Issue Environmental Stressors and Pathology of Marine Molluscs)
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18 pages, 4053 KiB  
Article
Trans-Media Kinematic Stability Analysis for Hybrid Unmanned Aerial Underwater Vehicle
by Tongjin Wei, Di Lu, Zheng Zeng and Lian Lian
J. Mar. Sci. Eng. 2022, 10(2), 275; https://doi.org/10.3390/jmse10020275 - 16 Feb 2022
Cited by 13 | Viewed by 2924
Abstract
In recent years, hybrid unmanned aerial underwater vehicles (HAUVs), which are capable of air–water trans-media motion, have been increasingly developed. For most HAUVs, air–water trans–media motion is a relatively dangerous and difficult process. Therefore, it is of great significance to study the particular [...] Read more.
In recent years, hybrid unmanned aerial underwater vehicles (HAUVs), which are capable of air–water trans-media motion, have been increasingly developed. For most HAUVs, air–water trans–media motion is a relatively dangerous and difficult process. Therefore, it is of great significance to study the particular process. This paper presents the first study on the kinematic stability of the air–water trans–media motion of HAUVs. First, a simplified dynamic model of HAUVs is proposed, including the hydrodynamic forces and the time–varying buoyancy. Then, based on the proposed model and the Hurwitz method, this paper derives the air–water trans–media kinematic stability criterion for HAUVs. This criterion can be applied to most air–water trans–media motions that satisfy the assumptions in this paper. Finally, this paper takes “Nezha”, a novel HAUV, as an example to analyze its air–water trans–media kinematic stability. The results show that the proposed criterion is effective in judging the vehicle’s design, including the geometry and thruster power, which are important factors in the performance of the trans–media process. Full article
(This article belongs to the Special Issue Frontiers in Deep-Sea Equipment and Technology)
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9 pages, 1312 KiB  
Article
Meridionalization as a Possible Resource for Fisheries: The Case Study of Caranx rhonchus Geoffroy Saint-Hilaire, 1817, in Southern Italian Waters
by Salvatore Coco, Alessandra Roncarati, Francesco Tiralongo and Alberto Felici
J. Mar. Sci. Eng. 2022, 10(2), 274; https://doi.org/10.3390/jmse10020274 - 16 Feb 2022
Cited by 8 | Viewed by 3595
Abstract
Climate change affects the shift range distribution of species, especially among mobile species, and this phenomenon can alter ecosystems and impacts human activities. Fishing is an anthropic activity that undergoes the effect not only of the introduction and increase of non-native species but [...] Read more.
Climate change affects the shift range distribution of species, especially among mobile species, and this phenomenon can alter ecosystems and impacts human activities. Fishing is an anthropic activity that undergoes the effect not only of the introduction and increase of non-native species but also of native thermophilic ones. Some of these species can become a commercially exploitable resource. However, this information is often obscured by the negative effects these species can cause to the environment. We investigated how the thermophilic species Caranx rhonchus, neglected in Italy, could become a relevant resource. We studied the nutritional profile and the presence of heavy metal contamination and compared these traits with those of a similar common Mediterranean species, namely Trachurus trachurus. The proximate composition was determined following the AOAC procedure, while the fatty acid profile was determined by GC/MS, and the mineral component was obtained by mass spectrometer (ICP-MS). Caranx rhonchus is a nutritionally good species, although it is little consumed and exploited. Increasing the market supply with new commercially exploitable emerging species would benefit local communities and the environment. Therefore, it is necessary to investigate how a shift of the range caused by climate change can provide benefits within the human dimension. Full article
(This article belongs to the Special Issue Coastal Fish Research II)
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9 pages, 787 KiB  
Article
Genotoxic Properties of Polystyrene (PS) Microspheres in the Filter-Feeder Mollusk Mytilus trossulus (Gould, 1850)
by Victor Pavlovich Chelomin, Andrey Alexandrovich Mazur, Valentina Vladimirovna Slobodskova, Sergey Petrovich Kukla and Nadezda Vladimirovna Dovzhenko
J. Mar. Sci. Eng. 2022, 10(2), 273; https://doi.org/10.3390/jmse10020273 - 16 Feb 2022
Cited by 15 | Viewed by 2950
Abstract
Microplastic pollution of the aquatic environment is one of the most serious environmental problems today. The potential environmental risks of such particles have become growing concerns in recent years, as direct or indirect exposure to these particles leads to adverse effects on marine [...] Read more.
Microplastic pollution of the aquatic environment is one of the most serious environmental problems today. The potential environmental risks of such particles have become growing concerns in recent years, as direct or indirect exposure to these particles leads to adverse effects on marine organisms. In this study, we investigated the potential risk of polystyrene (PS) microspheres on the genome integrity of cells of different tissues (gills and digestive gland) of the filter-feeder mollusk Mytilus trossulus, using a comet assay. With the help of the comet assay, we estimated the level of genome destruction in the cells of two different mussel tissues after short-term exposure to polystyrene. It was discovered that, despite their chemical inertness, PS microspheres that are 0.9 µm in diameter, at a concentration of 106 particles/L, exhibit genotoxic properties, which are expressed as a two-fold increase in the level of cell DNA damage of the mussel’s digestive gland. It is noted that, after exposure to PS, about half of the mussel’s digestive gland cells experienced damage in 25–35% of their DNA. In addition, the proportion of cells with significant DNA damage (50%) was about 5%. Given the unique role of the genome, DNA damage in these cells may be the earliest stage in the development of biochemical events that lead to toxic effects. These findings provide a basis for studying specific biomarkers of microplastic contamination. Full article
(This article belongs to the Special Issue Ecotoxicology of Aquatic Plastic Debris)
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